Hey, enter your proxy credentials in Firefox's built in Network Proxy manager. Go to about:preferences by typing it in your URL bar, and press enter. Scroll down until you see Network Proxy, and then click on Settings. You can configure it from there and it will save your changes.

I´m talking about the popup window asking me for my user and password every time i run firefox. I want to save that.

That's the master password -- you cannot save that. But you can remove it: https://support.mozilla.org/en-US/kb/reset-your-master-password-if-you-forgot-it

I´m not using master password and never used. I just want to save proxy credentials. Another info is that i´m using Active Directory authentication in the proxy

You cannot save this information.

but worked before, what´s changed?

Actually, let's try reinstalling the add-on, remove the add-on by going to about:addons and remove it, restart the browser, and then reinstall the add-on from here: https://addons.mozilla.org/en-US/firefox/addon/autoauth/

It´s the same, and i think autoauth is not working. It is so annoying to put the proxy credentials every time i start firefox.....

Additional info:

My proxy is Sophos, my user is an Active Direct account. I remember to change some things in about:config that had to do with NTLM......

• network.automatic-ntlm-auth.allow-proxies
• network.automatic-ntlm-auth.trusted-uris

• http://kb.mozillazine.org/network.automatic-ntlm-auth.trusted-uris
• http://kb.mozillazine.org/network.proxy.share_proxy_settings
• http://kb.mozillazine.org/network.automatic-ntlm-auth.allow-proxies

I´m going to try with a computer that belongs to my domain. Thanks

Same issue here. Not being prompted to save proxy credentials, meaning I have to enter every time browser is launched. Seems like a simple thing. Worked great for years until Quantum.

Mozilla really screwed this one up.